docs(tools): tool removal/consolidation runbook — ratified, audited, never autonomous

[williamzujkowski]

Part of #3850. Depends on #3852, #3840 (ladder ADR).

Context

The runbook: candidate signal → dedicated issue → human ratification via Epic D's consensus path → deprecation window (tool warns) → removal PR through the governor path (Epic B) → tier-transition/removal audit event. Consolidations additionally map old→new tool guidance for harness users.

Acceptance criteria

• Runbook doc indexed; references the Epic D ratification gate + Epic B review path
• The 46/47-count claims-registry entry updated as part of any removal (claims:check keeps it honest)
• Explicit statement: no code path may remove a tool registration autonomously

Evidence required

Docs gates.

Out of scope

Performing any removal.